Climate experts have long thought tropical forests were largely unaffected by minor increases in temperature, but a new study published in Sunday’s online edition of the journal Nature Climate Change has unearthed evidence to the contrary.

According to the study authors, scientists had previously believed slight warming did not affect tropical forests due to the fact that these ecosystems already exist in warm regions of the world. However, they found the forests are actually producing more flowers in response to slight increases in temperatures.

The researchers examined how fluctuations in temperature, cloud cover and rainfall impacted the number of flowers produced by tropical forests. They found clouds primarily have an affect over short-term seasonal growth, but that changes in longer-term growth appeared to temperature-related.

While previous research have used long-term flower production data, Florida State University researcher Stephanie Pau and her colleagues claim their work is the first to combine that data with direct estimates of cloud-cover based on information obtained from satellites.

“Tropical forests are commonly thought of as the lungs of the Earth and how many flowers they produce is one vital sign of their health,” explained Pau, who conducted the research while at the University of California, Santa Barbara National Center for Ecological Analysis and Synthesis (NCEAS). “However, there is a point at which forests can get too warm and flower production will decrease. We’re not seeing that yet at the sites we looked at, and whether that happens depends on how much the tropics will continue to warm.”

During the study, Pau led an international team of researchers as they studied both season and year-to-year flower production in two vastly different tropical forests: one, a seasonally dry forest on Barro Colorado Island in Panama, and the other and a rainforest in Luquillo, Puerto Rico. They found the Panamanian site had been producing more flowers at an average rate of three percent annually over the past several decades – an increase they believe can be attributed to warming temperatures in the region.

“With most projections of future climate change, people have emphasized the impact on high-latitude ecosystems because that is where temperatures will increase the most,” Pau said. “The tropics, which are already warm, probably won’t experience as much of a temperature increase as high-latitude regions. Even so, we’re showing that these tropical forests are still really sensitive to small degrees of change.”

Pau’s study “integrates ground and satellite observations over nearly three decades to tease apart the influence of temperature and cloudiness on local flower production,” added US Geological Survey Senior Scientist Julio Betancourt, who was not involved in the study. “It confirms other recent findings that, in the tropics, even a modest warming can pack quite a punch.”